I send "bunny bags" and "bunny boxes" to my nieces and nephews at Easter with small packages of candy, but otherwise I generally buy it the day after on clearance for chopping up to put in cookies. I also buy the special October Breast Cancer Awareness packages of M&Ms, especially for my niece who adores the color pink. :) Oh, and yes, I do buy Peeps on clearance for exploding in the microwave...the scrubbing involved in the clean-up is a great stress reliever! LOL ;)

I live in Germany, and Lindt for example makes some delicious chocolate specialties that you can only get around Christmas, so of course I buy them then :)
they wouldn't be special if you could buy them all year.
As for M&Ms, where only the color is different from the regular ones.. I only buy them if I decorate seasonal cupcakes with them, or if I had planned on buying them anyway.

Only AFTER said holiday is over...I buy the 50% off Halloween candy, Christmas candy, V-day candy, etc. the day after the holiday so I can get a good deal. I don't really eat much of it, but my husband loves it.

If I do purchase, it'll usually be for me to give to someone else. I try not to buy anything for myself (except for Cadbury Cream Eggs around Easter) and usually other people like my mom send me all the themed candy I could want.